Method for improving the readability during optical scanning of automatic car identification labels

ABSTRACT

A method for improving the readability during optical scanning of automatic car identification labels by applying a continuous coat to the labels of a thickened acid cleaner comprising an aqueous hydrochloric acid, an organic acid, a nonionic surfactant, an anionic surfactant and water.

United States Patent Otrhalek et al.

[451 Nov. 25, 1975 METHOD FOR IMPROVING THE READABILITY DURING OPTICALSCANNING OF AUTOMATIC CAR IDENTIFICATION LABELS Inventors: Joseph V.Otrhalek, Dearborn;

Robert E. Gansser, Wyandotte, both of Mich.

BASF Wyandotte Corporation, Wyandotte, Mich.

Filed: Oct. 1, 1974 Appl. No.: 510,891

Assignee:

US. Cl. 427/162; 134/3; 134/40; 252/136; 252/142; 427/401 Int. Cl. B05D5/06; BOSD 1/00; BOSD 3/00 Field of Search 134/3, 40; 252/136, 142;427/162, 401

[56] References Cited UNITED STATES PATENTS 3,650,965 3/1972 Cantor etal..... 252/106 3,793,221 2/1974 Otrhaiek et a1 252/136 PrimaryExaminerMichael R. Lusignan Attorney, Agent, or FirmNorbert M. Lisicki;Bernhard R. Swick; Robert E. Dunn 3 Claims, No Drawings METHOD FORIMPROVING THE READABILITY DURING OPTICAL SCANNING OF AUTOMATIC CARIDENTIFICATION LABELS BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to a method for improving thereadability during optical scanning of automatic car identificationlabels by applying a thickened acid cleaner composition thereto.Automatic car identification labels are composed of retro-reflectiveplastic materials which are attached to railroad cars for purposes ofchecking the location of the cars in transit. Due to the large numbersof railroad cars employed by various corporations, a system of checkingthe location and number of railroad cars was developed. This systememploys automatic scanning devices, in conjunction with computers, whichoptically scan a series of reflective tapes, of different colors, whichare attached to the side of the railroad car. The computer thentabulates the ownership of the car and its location. This informationmay then be employed to apply the proper demurrage charges. It may alsobe employed to trace the movements of the car from the point of originto its destination point. In order for the scanning devices to properlyidentify the car, it is, of course, necessary that the surface of theidentification labels be sufficiently clean that the optical scanner cantransmit the configuration and color of the labels to the computer.

2. Description of the Prior Art In the present state of the art theautomatic car identification labels are cleaned by apray application tothe railroad car of an alkaline or acid cleaner followed by handbrushing and rinsing. The cleaners used for this purpose must bevigorously and thoroughly brushed if adequate cleaning is to beobtained.

The use of acid in cleaning compositions is known. For instance, U.S.Pat. No. 2,257,467 discloses a solidified acid composition for cleaningtoilet bowls and the like wherein the composition consists of sodiumsilicate, water and hydrochloric acid. Another acid cleaner is disclosedin U.S. Pat. No. 3,271,319 wherein it is taught that stains can beremoved from glass surfaces by the use of an acid cleaner consisting ofwater, hydrofluoric acid, a carboxymethylcellulose thickener and a smallamount, usually less than 1 percent, of an alkyl sulfate or alkyl arylsulfonate wetting agent. A still more recent patent, U.S. Pat. No.3,622,391 teaches removing aluminide coatings from cobalt base or nickelbase superalloys by the use of a hydrofluoric acid and water compositionwhich permissibly includes a low foaming or nonfoaming wetting agent. Itis further disclosed that the composition can be thickened by adding acondensation product of ethylene oxide with a molecular weight of 4,000and gum tragacanth. However, the use of this composition requires afollow-up neutralization with an alkali solution followed by waterrinsing.

Mineral acids have also been used in cleaning compositions as adefoamer. This technique is illustrated in U.S. Pat. No. 3,650,965wherein the foaming qualities of nonionic surfactants for food industrycleaning can be reduced by the use of an organic acid coupled with amineral acid such as phosphoric acid, the acid component being more thanthe surfactant component.

It has also been known to clean transportation equipment such as trains,boxcars and the like by the use of an acid cleaner to remove siliceoussoils followed by an 2 alkaline cleaner to remove organic and oily soilsthen finally followed by water rinsing.

Two recently issued patents, U.S. Pat. No. 3,793,221 and 3,822,234disclose the composition of the instant invention and its use incleaning vehicles. These patents also teach the necessity for rinsingoff the acid cleaner.

SUMMARY OF THE INVENTION In accordance with this invention there isprovided a method for improving the readability during optical scanningof automatic car identification labels by applying thereon a coat of athickened acid cleaner comprising:

I. an aqueous hydrochloric acid in an amount from about 15 to about 40weight percent,

2. an organic acid selected from the group consisting of oxalic,tartaric, citric acid and mixtures thereof in an amount from about 1 toabout 6 weight percent,

3. a nonionic surfactant in an amount from about 7 to about 23 weightpercent,

4. an anionic surfactant in an amount from about 1 to about 7 weightpercent, and

5. water in an amount from about 76 to about 24 weight percent;

all weight percents being based on the total composition, provided thatthe said nonionic surfactant and the said anionic surfactant when takentogether constitute from about 10 to about 30 weight percent of saidcomposition and said nonionic surfactant constitutes from about to aboutweight percent of the combined weight percent of nonionic and anionicsurfactants.

This concentrate is used as is by application to the labels without anysubsequent alkaline or aqueous rinsing. The cleaner is allowed to remainon the surface of the labels for a few minutes prior to optical scanningby the automatic scanning devices. It has been found that this thickenedacid cleaner not only cleans the labels adequately without brushing butalso that the cleaner need not be rinsed off after application. In fact,it has been found that the unrinsed, unbrushed cleaner tends to leavethe surface of the labels brighter and easier to read by the opticalscanner than if it were rinsed from the surface.

The effect of this invention is:

l. the labels are in a brighter condition and easier to read than whenthey are cleaned by conventional means,

2. there is no scratching or undue wearing of the reflective surfacesince brushing is not necessary, thus prolonging the life of the label,and

3. there is a saving of both time and labor since rinsing is notrequired in the cleaning process.

The ordinary cleaners presently employed if allowed to remain on thelabels without rinsing present a dull surface which prevents the opticalscanner from reading the labels properly.

The acid cleaner can also be used by dilution of up to 1 volume ofcleaner with 3 volumes of water but preferably it is used in itsconcentrated form or at most a dilution of 1:1 by volume of cleaner towater.

DESCRIPTION OF THE PREFERRED EMBODIMENT The hydrochloric acid employedin this invention is that commercially available concentratedhydrochloric acid which has a concentration of 36 to 37 weight percent.It is within the scope of this invention to use as a partial replacementup to but no more than 50 percent by weight of hydrochloric acid, anequal weight amount of concentrated sulfuric acid or phosphoric acid.The sulfuric acid is considered to be that commercially available acidhaving a concentration of about 96 percent by we ght. The phosphoricacid, which is available commerc ally in different concentrations, forthe purpose of this invention is considered to have a concen trat on of75 percent by weight. Since the amount of water which is included in thecleaner concentrate varies from 24 to 76 percent, the hydrogen ionconcentration of the mineral acids is not critical. Generally, the useof sulfuric acid and/or phosphoric acid is not favored except foreconomic reasons. On a weight percent basis the acid cleaner of thisinvention contains from about to about 40 weight percent and morepreferably, the acid content will be from about to about 30 weightpercent.

The second component of the composition is an organic acid preferablyselected from the group consisting of oxalic, tartaric, citric acids ormixtures thereof in an amount from about 1 to about 6 weight percent andmore preferably in an amount from about 2 to about 4 weight percent.

The particular surfactants employed in the invented composition inaddition to having a cleaning effect also exhibit unusual thickeningproperties for this composition which were entirely unexpected.Therefore the surfactants of this invention are doubly critical. Thenon-ionic surfactant is present in an amount from ab ut 7 to ab ut 23weight percent of the final composit on and more prefe a ly in an amountfrom about 12 to 18 w ight percent.

The non o c surface active age ts which are advant s ed-sly employed inthe compositions of the invention are generally the polyoxyalkyleneadducts of hydrophobic ba es wherein the oxygen/carbon atom ratio in theoxyalkylene portion of the molecule is grea er than 0.40. Thosecompositions which are condensed with hydrophobic bases to provide apolyoxya kylene portion having an oxygen/carbon atom ratio greater than0.40 include ethylene oxide, butadiene dioxide and glycic ol, mixturesof these alkylene ox des with each other and with minor amounts ofpropylene oxide, butylene oxide, amylene oxide, styrene oxide, and otherhigher molecular weight alkylene ox des. Ethylene oxide, for example, iscondensed with the hydrophobic base in an amount sufficient to impartwater dispersibility or solubility and surface active properties to themolecule being prepared. The exact amount of ethylene oxide condensedwith the hydrophobic base will depend upon the chemical characteristicsof the base employed and is readily apparent to those of ordinary skillin the art relating to the synthesis of oxyalkylene surfactantcondensates.

Typical hydrophobic bases which can be condensed with ethylene oxide inorder to prepare nonionic surface active agents include monoandpolyalkyl pheno s, polyoxypropylene condensed with a base having fromabout 1 to 6 carbon atoms and at least one reactive hydrogen atom, fattyacids, fatty amides and fatty alcohols. The hydrocarbon ethers such asthe benzyl or lower alkyl ether of the polyoxyethylene surfactantcondensates are also advantageously employed in the compositions of theinvention.

Among the suitable nonionic surface active agents are thepolyoxyethylene condensates of alkyl phenols having from about 6 to 20carbon atoms in the alkyl 4 portion and from about 5 to 30 ethenoxygroups in the polyoxyethylene radical. The alkyl substituent on thearomatic nucleus may be octyl, diamyl, n-dodecyl, polymerized propylenesuch as propylene tetramer and trimer, isoctyl, nonyl, etc. The benzylethers of the polyoxyethylene condensates of monoalkyl phenols impartgood properties to'the compositions of the invention and a typicalproduct corresponds to the formula:

Higher polyalkyl oxyethylated phenols corresponding to the formula:

wherein R is hydrogen or an alkyl radical having from about 1 to 12carbon atoms, R and R are alkyl radicals having from about 6 to 16carbon atoms and n has a value from about 5 to 30 are also suitable asnonionic surface active agents. A typical oxyethylated polyalkyl phenolis dinonyl phenol condensed with 14 moles of ethylene oxide.

Other suitable nonionic surface active agents are cogeneric mixtures ofconjugated polyoxyalkylene compounds containing in their structure atleast one hydrophobic oxyalkylene chain in which the oxygen/carbon atomratio does not exceed 0.40 and at least one hydrophilic oxyalkylenechain in which the oxygen/carbon atom ratio is greater than 0.40.

Polymers of oxyalkylene groups obtained from propylene oxide, butyleneoxide, amylene oxide, styrene oxide, mixtures of such oxyalkylene groupswith each other and with minor amounts of polyoxyalkylene groupsobtained from ethylene oxide, butadiene dioxide, and glycidol areillustrative of hydrophobic oxyalkylene chains having an oxygen/carbonatom ratio not exceeding 0.40. Polymers of oxyalkylene groups obtainedfrom ethylene oxide, butadiene dioxide, glycidol, mixtures of suchoxyalkylene groups with each other and with minor amounts of oxyalkylenegroups obtained from propylene oxide, butylene oxide, amylene oxide andstyrene oxide are illustrative of hydrophilic oxyalkylene chains havingan oxygen/carbon atom ratio greater than 0.40.

Further suitable nonionic surface active agents are the polyoxyethyleneesters of higher fatty acids having from about 8 to 22 carbon atoms inthe acyl group and from about 5 to 30 ethenoxy units in the oxyethyleneportion. Typical products are the polyoxyethylene adducts of tall oil,rosin acids, lauric, stearic and oleic acids and the like. Additionalnonionic surface active agents are the polyoxyethylene condensates ofhigher fatty acid amines and amides having from about 8 to 22 carbonatoms in the fatty alkyl or acyl group and about 10 to 30 ethenoxy unitsin the oxyethylene portion. [1- lustrative products are coconut oilfatty acid amides condensed with about 5 to 30 moles of ethylene oxide.

Other suitable polyoxyallcylene nonionic surface active agents are thealkylene oxide adducts of higher aliphatic'alcohols and thioalcoholshaving from about 8 to 22 carbon atoms in the aliphatic portion andabout to 30 oxyalkylene portiomTypical products are: (l) synthetic fattyalcohols, such asn-decyl, 'n-undecyl, ndodecyl, n-tridecyl,n-tetradecyl, n-hex'a'decyl, noctadecyl and mixtures thereofcondensedwith 5 to 30 moles of ethylene oxide; (2) a mixture of normal fattyalcohols condensed with 8 to 20 moles of ethylene oxide and capped withbenzyl halide or an alkyl halide, (3) a mixture of normal fatty alcoholscondensed with 5 to 30 moles of a mixture of ethylene and propyleneoxides, (4),-a mixture of several fatty alcohols condensed sequentiallywith 2 to 20 moles of ethylene oxide and 3 to moles of propylene oxide,in either order, (5) a mixture of normal fatty alcohols condensed with amixture of propylene and ethylene oxides, in which the oxygen/carbonatom ratio is less than 0.40 followed by a mixture of propylene andethylene oxides in which the oxygen/carbon atom ratio is greater than0.40 or a linear secondary alcohol condensed with 3 to 30 moles ofethylene oxide, (6) a linear secondary alcohol condensed with a mixtureof propylene and ethylene oxides, (7) a linear secondary alcoholcondensed with a mixture of ethylene, propylene, and higher alkyleneoxides.

Of the foregoing described nonionic surface active agents orsurfactants, a particularly preferred group is the polyethylene oxidecondensates of alkyl phenols, particularly those having an alkyl groupcontaining from about 6 to 12 carbon atoms in either a straight chain orbranch chain configuration with ethylene oxide, the ethylene oxide beingpresent in amounts equal to 5 to 25 moles of ethylene oxide per mole ofalkyl phenol. This group of surfactants is exemplified by octylphenoxypolyethoxyethanol.

The second component of the surfactant system of this inventedcomposition is an anionic surfactant which is present in an amount fromabout 1 to about 7 weight percent and more preferably in an amount fromabout 2 to about 3 percent.

Anionic synthetic non-soap detergents can be broadly described asorganic sulfuric and sulfonic acid reaction products having in theirmolecular structure an alkyl radical containing from about 8 to about 22carbon atoms and a radical selected from the group consisting ofsulfonic acid and sulfuric acid ester radicals. (Included in the termalkyl is the alkyl portion of higher acyl radicals.) Important examplesof the synthetic detergents which from a part of the preferredcompositions of the present invention are: (1) those obtained bysulfating the higher alcohols (Cg-C 3 carbon atoms) produced by reducingthe glycerides of tallow or coconut oil, (2) alkyl benzene sulfonates,in which the alkyl group contains from about 9 to about carbon atoms,including those of the types described in US. Pat. Nos. 2,220,099 and2,477,383 (the alkyl radical can be a straight or branched aliphaticchain), (3) alkyl glyceryl ether sulfonates, especially those ethers ofthe higher alcohols derived from tallow and coconut oil, (4) coconut oilfatty acid monoglyceride sulfates and sulfonates, (5) sulfuric acidesters of the reaction product of one mole of a higher fatty alcohol(e.g., tallow or coconut oil alcohols) and about 1 to 6 moles ofethylene oxide, (6) sulfuric acid and sulfonic acid esters of thereaction product of one mole of a higher fatty oil (e.g., coconut orcastor oil) and about 1 to 6 moles of ethylene oxide, (7) alkylphenolethylene oxide ether sulfate with about 1 to about 10 units ofethylene oxide per molecule and in which the alkyl radicals contain from8 to about 12 carbon atoms, (8) the reaction product of fatty acidsesterified with isethionic acid where, for example, the fatty acids arederived from coconut oil, (9) fatty acid amide of a methyl tauride inwhich the fatty acids, for example, are derived from coconut oil; andothers known in the art, a number being specifically set forth in U.S.Pat. Nos. 2,486,921, 2,486,922 and 2,396,278. While less preferred thesodium and potassium salts of the foregoing sulfonic and sulfuric acidand/or ester anionic surfactants can also be used. The foregoing anionicsurfactants are further exemplified in McCutcheons Detergents &Emulsifiers, 1972 Annual, Allured Publishing Corporation, Ridgewood, NewJersey.

Particularly suited for the process and composition of this inventionare the alkyl or aryl sulfonic acid anionic surfactants exemplified by alinear alkyl benzene sulfonic acid.

When taken together in considering the foregoing nonionic and anionicsurfactants, it is critical to the success of this invention that thetotal amount of surfactant present constitute from about 10 to about 30weight percent of the total cleaner composition and that the non-ionicportion of the total surfactant portion be from about to about weightpercent.

The final component of the invented cleaning composition is water whichis present in an amount from about 76 to about 24 percent by weight andpreferably in an amount from about 74 to about 45 weight percent.

In addition to the foregoing ingredients, as is well known in thedetergent art, dyes, perfumes, corrosion inhibitors and the like may beadded to the cleaning composition.

The compositions of this invention are prepared by mixing techniqueswell known to those skilled in the art. A convenient procedure for thepreparation of the composition at room temperature would be to chargethe water to the vessel, add in the organic acids followed by thenonionic surfactant and the anionic surfactant and finally thehydrochloric acid. If it is desirable to add other optional modifiers tothe composition such as dyes, perfumes, and inhibitors, they can beadded as convenient during the preparation of the composition.

As mentioned above, the composition of this invention has been disclosedin US. Pat. No. 3,793,22l which disclosure is hereby included byreference.

The acid cleaner concentrate is flowed onto the identification label inan amount such that a thin, continuous film covering the label isobtained. Within a few minutes the labels are clean and shiny. In orderto obtain best results the acid cleaner is not rinsed off.

The practice of this invention is illustrated but not limited by theexamples given below. Unless otherwise noted all parts or percents areby weight.

EXAMPLE 1 An open mixing vessel was charged with 54 parts of water and 3parts of oxalic acid dihydrate was dissolved therein. Octylphenoxypolyethoxyethanol, 14 parts, was added next, followed by 2.5 parts of alinear alkyl benzene sulfonic acid. Finally 26.5 parts of 37%hydrochloric acid were added. The thickened acid cleaner was thendischarged from the mixing vessel.

The foregoing concentrate was sprayed onto the labels of 32 ore hopperrailroad cars of a train moving at 4 mph. The labels were sufficientlydirty that none 7 could be read by the automatic optical scanningdevice. Approximately ten minutes after spraying, the train passed ascanner which correctly read 23 of the labels. After brushing andrinsing, the train again passed by a scanning station which read only 15of the labels of which only 8 were correct.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A method for improving during optical scanning, the readability ofautomatic car identification labels comprising a. applying a continuouscoat of a thickened acid cleaner composition consisting essentiallyof 1. an aqueous hydrochloric acid in an amount from about 15 to about40 weight percent,

2. an organic acid selected from the group consisting of oxalic,tartaric, citric acid and mixtures thereof in an amount from about 1 toabout 6 weight percent,

3. a nonionic surfactant in an amount from about 7 to about 23 weightpercent,

8 4. an anionic surfactant in an amount from about 1 to about 7 weightpercent, and 5. water in an amount from about 76 to about 24 weightpercent; all weight percents being based on the total composition,provided that the said nonionic surfactant and the said anionicsurfactant when taken together constitute from about 10 to about 30weight percent of said composition and said nonionic surfactantconstitutes from about to about weight percent of the combined weightpercent of nonionic and anionic surfactants,

b. allowing said coat to remain on said labels during said scanning.

2. The method of claim 1 wherein the acid cleaner composition is dilutedwith water up to a 1:3 volume ratio of cleaner to water prior toapplication of said diluted composition to the labels.

3. The method of claim 1 wherein the acid cleaner composition is dilutedwith water in a lzl volume ratio of cleaner to water prior toapplication of said diluted composition to the labels.

1. A METHOD FOR IMPROVING DURING OPTICAL SCANNING, THE READABILITY OFAUTOMATIC CAR IDENTIFICATION LABELS COMPRISING A. APPLYING A CONTINOUSCOAT OF A THICKENED ACID CLEANER COMPOSITION CONSISTING ESSENTIALLYOF
 1. AN AQUEOUS HYDROCHLORIC ACID IN AN AMOUNT FROM ABOUT 15 TO ABOUT40 WEIGHT PERCENT,
 2. AN ORGANIC ACID SELECTED FROM THE GROUP CONSISTINGOF OXALIC, TATARIC, CITRIC ACID AND MIXTURES THEREOF IN AN AMOUNT FROMABOUT 1 TO ABOUT 6 WEIGHT PERCENT,
 2. an organic acid selected from thegroup consisting of oxalic, tartaric, citric acid and mixtures thereofin an amount from about 1 to about 6 weight percent,
 2. The method ofclaim 1 wherein the acid cleaner composition is diluted with water up toa 1:3 volume ratio of cleaner to water prior to application of saiddiluted composition to the labels.
 3. The method of claim 1 wherein theacid cleaner composition is diluted with water in a 1:1 volume ratio ofcleaner to water prior to application of said diluted composition to thelabels.
 3. a nonionic surfactant in an amount from about 7 to about 23weight percent,
 3. A NONIONIC SURFACTANT IN AN AMOUNT FROM ABOUT 7 TOABOUT 23 WEIGHT PERCENT,
 4. AN ANIONIC SURFACTANT IN AN AMOUNT FROMABOUT 1 TO ABOUT 7 WEIGHT PERCENT, AND
 4. an anionic surfactant in anamount from about 1 to about 7 weight percent, and
 5. water in an amountfrom about 76 to about 24 weight percent; all weight percents beingbased on the total composition, provided that the said nonionicsurfactant and the said anionic surfactant when taken togetherconstitute from about 10 to about 30 weight percent of said compositionand said nonionic surfactant constitutes from about 75 to about 90weight percent of the combined weight percent of nonionic and anionicsurfactants, b. allowing said coat to remain on said labels during saidscanning.
 5. WATER IN AN AMOUNT FROM ABOUT 76 TO A OUT 24 WEIGHTPERCENT; ALL WEIGHT PERCENTS BEING BASED ON THE TOTAL COMPOSITION,PROVIDED THAT THE SAID NONIONIC SURFACTANT AND THE SAID ANIONICSURFACTANT WHEN TAKEN TOGETHER CONSITUTED FROM ABOUT 10 TO ABOUT 30WEIGHT PERCENT OF SAID COMPOSITION AND SAID NONIONIC SURFACTANTCONSTITUTES FROM ABOUT 75 TO ABOUT 90 WEIGHT PERCENT OF THE COMBINEDWEIGHT PERCENT OF NONIONIC AND ANIONIC SURFACTANTS. B. ALLOWING SAIDCOAT TO REMAIN ON SAID LABELS DURING SAID SCANNING.